WASHINGTON (AP) — The House will vote Thursday on GOP legislation to repeal and replace Barack Obama’s Affordable Care Act, as Republicans finally aim to deliver on seven years of campaign promises that helped them gain control of Congress and the White House.

But the move announced late Wednesday by GOP leaders also carries extreme political risk, as House Republicans prepare to endorse a bill that boots millions off the insurance rolls and may not even survive the Senate.

“We will pass this bill,” House Majority Leader Kevin McCarthy, R-Calif., confidently predicted after a day of wrangling votes and personal arm-twisting by President Donald Trump.

After an earlier defeat when Republican leaders were forced to pull the bill for lack of votes, the decision to move forward indicated confidence on the part of GOP leaders. Failure would be catastrophic. But a successful outcome would make good on the GOP’s No. 1 goal of undoing Obama’s signature legislative achievement, and provide a long-sought win for Trump, who has been in office more than 100 days without a significant congressional victory save Senate confirmation of a Supreme Court justice.

The White House had aggressively pushed House leaders to act, and Trump got heavily involved in recent days, working the phones and personally agreeing to changes earlier Wednesday that brought two pivotal Republicans back on board. Reps. Fred Upton of Michigan and Billy Long of Missouri emerged from a White House meeting with Trump saying they could now support the bill, thanks to the addition of $8 billion over five years to help people with pre-existing conditions.

“‘We need you, we need you, we need you,'” Long described as the message from a president eager for a victory.

Democrats stood firmly united against the health bill. But they generally applauded a separate $1 trillion-plus spending measure to keep the government running, which passed the House on a bipartisan vote of 309-118 earlier Wednesday.

The latest iteration of the GOP health care bill would let states escape requirements that insurers provide a menu of basic services like preventive care and charge healthy and seriously ill customers the same rates – changes that brought a key group of conservatives on board last week. Overall, the legislation would cut the Medicaid program for the poor, eliminate fines for people who don’t buy insurance and provide generally skimpier subsidies. The American Medical Association, AARP and other consumer and medical groups are opposed. The AMA issued a statement saying the changes sought by Upton and Long “tinker at the edges without remedying the fundamental failing of the bill – that millions of Americans will lose their health insurance as a direct result.”

If the GOP bill became law, congressional analysts estimate that 24 million more Americans would be uninsured by 2026, including 14 million by next year.

When the health bill does come to a vote Thursday it will be without an updated analysis from the nonpartisan Congressional Budget Office about its cost and affect, a point Democrats complained about bitterly.

“Forcing a vote without a CBO score shows that Republicans are terrified of the public learning the full consequences of their plan,” said House Minority Leader Nancy Pelosi, D-Calif. “But tomorrow, House Republicans are going to tattoo this moral monstrosity to their foreheads, and the American people will hold them accountable.”

Even with Upton and Long in the “yes” column, GOP leaders had spent the day hunting for votes among wary moderates. More than a dozen opponents said they were still no despite the latest changes. GOP leaders can lose only 22 from their ranks and still pass the bill, and an Associated Press tally found 19 opposed even after Upton and Long got on board. But late in the day Wednesday at least two more Republicans – Daniel Webster of Florida and David Young of Iowa – also reversed their opposition and announced support for the bill.

Even so, Thursday’s margin could be razor-thin, much like when “Obamacare” itself cleared the House in 2010 on a party-line vote of 219-212. The GOP has been trying ever since to repeal the law even as around 20 million Americans gained coverage under it. On Thursday Republicans might succeed for the first time in passing a repeal bill that may have a chance of getting signed into law.

As they have throughout the debate, Republicans argued that Obama’s health law is collapsing under its own weight, and they must intervene to save it. They argue that their plan will provide consumers with lower premiums and more choices, removing the unpopular mandates that require most Americans to carry insurance or face fines. Several Republican lawmakers pointed to news out of Iowa this week that the last carrier of individual health insurance policies in most of the state might stop offering them to residents.

“That’s why we have to make sure this passes, to save those people from Obamacare that continues to collapse,” McCarthy said.

Separately, on the spending bill to keep the government running, Trump and GOP leaders hailed it as a victory, citing increases in money for the military. The $1.1 trillion spending bill was the bipartisan result of weeks of negotiations in which top Democrats like Pelosi successfully blocked Trump’s most controversial proposals, including a down payment on his oft-promised Mexico border wall, cuts to popular domestic programs, and new punishments for so-called sanctuary cities.

Now that it’s passed the House, the mammoth, 1,665-page measure to fund the government through September heads to the Senate, which is also expected to approve it. Trump has promised to sign it.